RT Journal Article SR Electronic T1 Autoimmune switch from hyperthyroidism to hypothyroidism in Graves’ disease JF BMJ Case Reports JO BMJ Case Reports FD BMJ Publishing Group Ltd SP e236465 DO 10.1136/bcr-2020-236465 VO 13 IS 11 A1 Preethi Padmanaban A1 Rohit Jain YR 2020 UL http://casereports.bmj.com/content/13/11/e236465.abstract AB We report a case of a 21-year-old young woman who was initially diagnosed with hyperthyroidism secondary to Graves’ disease and spontaneously switched to hypothyroidism in a year. While most autoimmune hypothyroidism is due to Hashimoto’s disease, in her case, we suspect that her hypothyroidism is due to a switch of antibody dominance from thyroid stimulating hormone (TSH) receptor-stimulating antibody (TS Ab) to TSH receptor-blocking antibody (TB Ab). Switching from dominant TS Ab activity to dominant TB Ab activity is a rare phenomenon. Optimal management of this condition is not known. Loss of follow-up and medication non-adherence has made medical management in this young woman of reproductive age further challenging.